JP2003160603A - Modified diene polymer rubber, production method thereof and rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a modified diene polymer rubber having excellent fuel cost saving property, a production method thereof and a rubber composition using the polymer rubber, particularly, to provide a rubber most suitably used as a rubber for an automotive tire having excellent fuel cost saving property. <P>SOLUTION: The modified diene polymer rubber can be obtained by reacting 1, 1-diphenylethylene compound represented by following formula (1) with an active conjugated diene polymer having an alkali metal at the end thereof obtained by polymerizing a conjugated diene monomer or a combination of a conjugated diene monomer with an aromatic vinyl monomer in a hydrocarbon solvent in the presence of an alkali metal catalyst (wherein R1 and R2 each represent an alkyl group or an alkoxy group having from 1 to 8 carbon atoms). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a modified diene polymer rubber, a method for producing the same, and a rubber composition. More specifically, the present invention relates to a modified diene polymer rubber which is excellent in impact resilience and therefore excellent in fuel economy, a method for producing the same, and a rubber composition using the polymer rubber.

[0002]

2. Description of the Related Art Conventionally, a styrene-butadiene copolymer obtained by an emulsion polymerization method has been known as a rubber for automobile tires. However, the copolymer is inferior in impact resilience, and therefore has a problem that it is not preferable from the viewpoint of fuel saving. Therefore, many attempts have been made to improve it. For example, in a hydrocarbon solvent,
A method has been proposed in which an organolithium compound is used as a polymerization initiator and butadiene and styrene are copolymerized in the presence of a microstructure modifier composed of a Lewis base such as ether (for example, JP-A-60-72907). reference.). Furthermore,
Japanese Patent Publication No. 2540901 discloses a method of reacting a specific acrylamide compound at the terminal of an alkali metal to obtain a modified diene copolymer rubber having improved fuel economy. However, the demand for improved fuel economy has become more advanced against the backdrop of environmental considerations in recent years, and conventional copolymers are not always satisfactory when they are in light of such high requirements in recent years. Was not.

[0003]

In view of the present situation, the problem to be solved by the present invention is to provide a modified diene polymer rubber excellent in fuel economy, a method for producing the same, and a rubber composition using the polymer rubber. To provide things.

[0004]

That is, the first invention of the present invention is to polymerize a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent using an alkali metal catalyst. A modified diene-based polymer rubber obtained by reacting an active conjugated diene-based polymer having an alkali metal terminal thus obtained with a 1,1-diphenylethylene compound represented by the following general formula (1) It is a thing. (In the formula, R ₁ and R ₂ represent an alkyl group or an alkoxy group having a carbon number of 1 to 8.) The second invention of the present invention is a conjugated diene monomer or a conjugated diene in a hydrocarbon solvent. For the active conjugated diene-based polymer having an alkali metal terminal, which is obtained by polymerizing a monomer and an aromatic vinyl monomer using an alkali metal-based catalyst, the above general formula (1)
The present invention relates to a method for producing a modified diene polymer rubber in which a 1,1-diphenylethylene compound represented by A third aspect of the present invention relates to a rubber composition containing the modified diene polymer rubber in the rubber component in an amount of 10% by weight or more.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The modified diene polymer rubber of the present invention is obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent using an alkali metal catalyst. A modified diene polymer rubber obtained by reacting an active conjugated diene polymer having an alkali metal terminal with the 1,1-diphenylethylene compound represented by the general formula (1).

As the conjugated diene monomer, 1,3-butadiene, isoprene, 1,3-pentadiene (piperine), 2,3-dimethyl-1,3-butadiene, 1,3
-Hexadiene and the like can be mentioned, and among these, 1,3-butadiene and isoprene are preferable from the viewpoint of the physical properties of the resulting copolymer and the availability in industrial practice.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, and the like. Styrene is preferred from the viewpoints of physical properties and availability for industrial implementation.

The hydrocarbon solvent is one which does not deactivate the alkali metal catalyst, and a suitable hydrocarbon solvent is selected from aliphatic hydrocarbons, aromatic hydrocarbons and alicyclic hydrocarbons, and particularly has a carbon number. Propane having 2 to 12 pieces,
n-butane, iso-butane, n-pentane, iso-
Pentane, n-hexane, cyclohexane, propene,
1-butene, iso-butene, trans-2-butene,
Cis-2-butene, 1-pentene, 2-pentene, 1-
Examples thereof include hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like. Also,
These solvents can be used as a mixture of two or more kinds.

As the alkali metal type catalyst, lithium,
Examples thereof include metals such as sodium, potassium, rubidium, and cesium, hydrocarbon compounds containing these metals, and complexes of the metals with polar compounds. The preferred alkali metal catalyst is 2
Examples thereof include lithium or sodium compounds having 20 carbon atoms, and specific examples thereof include ethyl lithium, n-propyl lithium and iso-.
Propyl lithium, n-butyl lithium, sec-butyl lithium, t-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium 4-cyclopentyl Examples thereof include lithium, 1,4-dilithio-butene-2, sodium naphthalene, sodium biphenyl, potassium-tetrahydrofuran complex, potassium diethoxyethane complex, and sodium salt of α-methylstyrene tetramer.

In the present invention, a 1,1-diphenylethylene compound represented by the following general formula (1) is used.

In the formula, R ₁ and R ₂ represent an alkyl group or an alkoxy group having 1 to 8 carbon atoms. Preferably, R ₁ and R ₂ are a methyl group, an ethyl group, a propyl group, a butyl group,
A methoxy group, an ethoxy group, a propoxy group or a butoxy group. Specific examples of the 1,1-diphenylethylene compound include 1- (4-N, N-dimethylaminophenyl) -1-phenylethylene, 1- (4-N, N-diethylaminophenyl) -1-phenylethylene, 1-
(4-N, N-dipropylaminophenyl) -1-phenylethylene, 1- (4-N, N-dibutylaminophenyl) -1-phenylethylene, 1- (4-N, N-dimethoxyaminophenyl) -1-phenylethylene, 1
-(4-N, N-diethoxyaminophenyl) -1-phenylethylene, 1- (4-N, N-dipropoxyaminophenyl) -1-phenylethylene, 1- (4-N,
N-dibutoxyaminophenyl) -1-phenylethylene and the like can be mentioned, but from the viewpoint that fuel efficiency can be remarkably improved and solubility in a solvent is excellent, 1- (4-
N, N-dimethylaminophenyl) -1-phenylethylene is preferred.

The modified diene polymer rubber of the present invention is an alkali metal terminal obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent using an alkali metal catalyst. It is obtained by reacting the 1,1-diphenylethylene compound represented by the general formula (1) with an active conjugated diene polymer having

As the polymerization monomer, only the conjugated diene monomer may be used, or the conjugated diene monomer and the aromatic vinyl monomer may be used in combination. When the conjugated diene monomer and the aromatic vinyl monomer are used in combination, the ratio of both is preferably 50/50 to 90/10 by weight ratio of conjugated diene monomer / aromatic vinyl monomer, and more preferably 55/45 to 85/15. Is. If the ratio is too small, the polymer rubber may be insoluble in the hydrocarbon solvent and uniform polymerization may not be possible, while if the ratio is too large, the strength of the polymer rubber may be lowered. Further, when the conjugated diene monomer and the aromatic vinyl monomer are used in combination, a random copolymer is desirable. In the case of a block copolymer, the fuel economy of a vulcanized rubber may be significantly reduced.

At the time of polymerization, it is possible to use a commonly used one such as an alkali metal catalyst, a hydrocarbon solvent, a randomizer, and a vinyl bond content regulator of a conjugated diene unit. , Not particularly restricted.

In order to adjust the vinyl bond content of the conjugated diene part, various compounds can be used as the Lewis basic compound, but ether compounds or tertiary amines are used.
It is preferable in terms of availability in industrial practice. Examples of the ether compound include cyclic ethers such as tetrahydrofuran, tetrahydropyran, and 1,4-dioxane; aliphatic monoethers such as diethyl ether and dibutyl ether; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether,
Aliphatic ethers such as diethylene glycol dibutyl ether; aromatic ethers such as diphenyl ether and anisole. Examples of the tertiary amine compound include triethylamine, tripropylamine,
In addition to tributylamine, N, N, N ', N'-
Examples thereof include tetramethylethylenediamine, N, N-diethylaniline, pyridine and quinoline.

The amount used in the production by adding the 1,1-diphenylethylene compound of the present invention to an active conjugated diene polymer having an alkali metal terminal is an amount of an alkali metal catalyst used in adding an alkali metal. The amount is usually 0.1 to 10 mol, preferably 0.5 to 1 mol.
2 mol. If the amount used is too small, the effect of improving fuel economy is small, and if it is too large, it remains in the polymerization solvent. Therefore, when the solvent is recycled, a separation step from the solvent is required. Etc. are economically unfavorable.

Since the reaction between the 1,1-diphenylethylene compound and the active conjugated diene polymer having an alkali metal terminal occurs rapidly, the reaction temperature and reaction time can be selected within a wide range, but in general, The temperature is from room temperature to 80 ° C. and from several seconds to several hours. The reaction may be carried out by bringing the alkali metal-containing diene polymer and the 1,1-diphenylethylene compound into contact with each other. For example, the diene polymer is polymerized using an alkali metal catalyst, and the diene polymer is added to the polymer solution. The one,
A method of adding a predetermined amount of the 1-diphenylethylene compound can be exemplified as a preferable embodiment, but the method is not limited to this method.

From the viewpoint of kneading processability, the cup represented by the general formula RaMXb is added to the active conjugated diene polymer before or after the reaction of the alkali metal-containing diene polymer and the 1,1-diphenylethylene compound. A ring agent is preferably added (wherein R is an alkyl group, an alkenyl group, a cycloalkenyl group or an aromatic hydrocarbon group, M is a silicon or tin atom, X is a halogen atom, and a is 0 to 2).
, And b represents an integer of 2 to 4). The amount is usually 0.03 to 0.4 mol, preferably 0.05 to 0.3 mol, per mol of the alkali metal catalyst used. If the amount used is too small, the processability improving effect is small. On the contrary, if the amount is too large, the number of alkali metal terminals that react with the 1,1-diphenylethylene compound is small, and the fuel saving improving effect is small.

The modified diene polymer rubber thus obtained has a 1,1-diphenylethylene compound (alkylamino group or alkoxyamino group) introduced at the molecular end. After the completion of the reaction, the modified diene polymer rubber is used as it is in the coagulation method used in the production of rubber by ordinary solution polymerization such as addition of a coagulant from the reaction solvent or steam coagulation, and the coagulation temperature is not limited at all. Not done.

The crumb separated from the reaction system can be dried by using a band drier, an extrusion type drier or the like used in the production of ordinary synthetic rubber, and the drying temperature is not limited at all.

Thus, the modified diene polymer rubber of the present invention is obtained.

The Mooney viscosity (ML _{1 + 4} ) of the modified diene polymer rubber is preferably 10 to 200,
More preferably, it is 20 to 150. If the Mooney viscosity is too low, mechanical properties such as tensile strength of the vulcanizate may deteriorate, while if the viscosity is too high, miscibility is poor when used in combination with other rubbers, making processability difficult. Therefore, the mechanical properties of the vulcanizate of the obtained rubber composition may deteriorate.

The vinyl bond content of the conjugated diene part of the modified diene polymer rubber is preferably 10 to 70%, more preferably 15 to 60%. If the content is too low, the glass transition temperature of the polymer will be low, and when used as a polymer for a tire, the grip performance may be poor. On the other hand, if the content is too high, the glass transition temperature of the polymer will be low. The temperature may rise and the impact resilience may be poor.

The modified diene polymer rubber of the present invention is a rubber composition containing other rubber components, various additives and the like.

Other rubber components include emulsion-polymerized styrene-butadiene copolymer rubber, polybutadiene rubber by solution polymerization (anionic polymerization catalyst, ziegler type catalyst), butadiene-isoprene rubber copolymer rubber, styrene-butadiene copolymer. Includes rubber and natural rubber,
One or more of these rubbers are selected and used according to the purpose. When another rubber component is used, the proportion of the modified diene polymer rubber of the present invention in all rubber components is preferably 10% by weight or more, more preferably 20% by weight or more. If the proportion of the modified diene polymer rubber of the present invention is too small, the degree of improvement in impact resilience is small and the processability is not improved.

The additive may be selected from those commonly used in the rubber industry, and is not particularly limited as long as it is suitable for the purpose of use of the rubber composition. Normally, sulfur is used as the vulcanization system,
Stearic acid, zinc white, various vulcanization accelerators (thiazole-based, thiuram-based, sulfenamide-based, etc.) or organic peroxides, and reinforcing agents such as various grades of carbon black such as HAF and ISAF, or silica. As the filler, calcium carbonate, talc, etc. are used, and as the other additives, extending oil, processing aid, antiaging agent, etc. are used. The carbon black or silica is preferably used in an amount of 10 to 150 parts by weight based on 100 parts by weight of the rubber component. If the amount of carbon black or silica is less than 10 parts by weight, the reinforcing effect is insufficient, and if it exceeds 150 parts by weight, problems such as reduced elongation may occur. The type and amount of the other additives are selected according to the purpose of use of the rubber composition and are not particularly limited in the present invention.

To obtain the rubber composition, the rubber component and various additives may be kneaded by using a mixer such as a roll or Banbury. The rubber composition is vulcanized and used.

Since the rubber composition of the present invention has excellent impact resilience, it can be optimally used for automobile tires having excellent fuel economy. Further, the rubber composition of the present invention is used for shoe soles, flooring agents,
It can be used as a raw material rubber for various industrial uses such as for vibration-proof rubber.

[0029]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Production Example: Synthesis of 1- (4-N, N-dimethylaminophenyl) -1-phenylethylene 4-N, N in 100 ml of tetrahydrofuran (THF)
80 ml of a THF solution obtained by reacting a solution of 25 g of dimethylaminobenzophenone with methyltriphenylphosphonium bromide and potassium t-butoxide.
The reaction product was slowly added to the reaction solution at 0 ° C. for 4 hours, and the obtained product was purified to obtain the title compound.

Example 1 A stainless steel polymerization reactor having an internal volume of 20 liters was washed,
After drying and replacing with dry nitrogen, 1,3-butadiene 1
420 g, styrene 580 g, tetrahydrofuran 1
22 g, 10.2 kg of hexane, and n-butyllithium (11.0 mmol of n-hexane solution) were added, and polymerization was carried out at 65 ° C. for 3 hours while stirring. After completion of polymerization, 1-
After adding 11.0 mmol of (4-N, N-dimethylaminophenyl) -1-phenylethylene and reacting for 60 minutes under stirring, 10 ml of methanol was added and further stirred for 5 minutes. After that, the contents of the polymerization reaction vessel were taken out, 10 g of 2,6-di-t-butyl-p-cresol (Sumilyzer BHT manufactured by Sumitomo Chemical Co., Ltd .: hereinafter the same) was added, and most of the hexane was evaporated. It was dried under reduced pressure at 55 ° C. for 12 hours to obtain a polymer rubber.

Example 2 Polymerization was carried out using n-butyllithium (n-hexane solution 17.2 mmol) in Example 1, and after completion of the polymerization, 2.24 mmol of silicon tetrachloride was added for coupling, and 1- (4-N, N-Dimethylaminophenyl) -1-phenylethylene was treated in the same manner except that 8.28 mmol was added, and a polymer rubber was obtained and evaluated.

Comparative Example 1 A stainless steel polymerization reactor having an internal volume of 20 liters was washed,
After drying and replacing with dry nitrogen, 1,3-butadiene 1
420 g, styrene 580 g, tetrahydrofuran 12
2 g, hexane 10.2 kg, n-butyl lithium (n
-Hexane solution 11.1 mmol) was added, and polymerization was carried out at 65 ° C for 3 hours with stirring. After completion of the polymerization, 10 ml of methanol was added and the mixture was further stirred for 5 minutes. Then, the contents of the polymerization reaction vessel were taken out and 10 g of 2,6-di-
After adding t-butyl-p-cresol (Sumilyzer BHT manufactured by Sumitomo Chemical Co., Ltd .: the same hereinafter) and evaporating most of the hexane, the polymer was dried under reduced pressure at 55 ° C for 12 hours to obtain a polymer rubber.

The polymer rubbers obtained in Examples 1 and 2 and Comparative Example 1 were measured and evaluated as follows. Mooney viscosity of polymer rubber Measured at 100 ° C. according to JIS K-6300. Vinyl Content of Polymer Rubber Determined by infrared spectroscopy. Styrene content of polymer rubber It was measured by a refractive index method. Vulcanized rubber impact resilience According to the formulation in Table 1, kneaded with a Labo Plastomill to obtain a compounded rubber, which was molded into a sheet with a 6-inch roll and then vulcanized under the conditions of 160 ° C. for 45 minutes. To obtain a vulcanized rubber. With respect to the vulcanized rubber, the impact resilience at 60 ° C. was measured using a Lupkeresierien tester. Table 2 shows the measurement and evaluation results.

[0035]

[Table 1] * 1: Ultrasil VN3-G (manufactured by Degussa Co., Ltd.) * 2: Si69 (manufactured by Degussa) * 3: X-140 (aroma oil manufactured by Kyodo Oil Co., Ltd.) * 4: Antigen 3C (Anti-aging agent manufactured by Sumitomo Chemical Co., Ltd.) ) * 5: Soxinol CZ (Sumitomo Chemical Co., Ltd. vulcanization accelerator) * 6: Soxinol D (Sumitomo Chemical Co., Ltd. vulcanization accelerator) * 7: Sunnock N (Ouchi Shinko Chemical Co., Ltd.)

[0036]

[Table 2] * 1 Modified compound A: 1- (4-N, N-dimethylaminophenyl) -1
-Phenylethylene

Example 3 Using a polymer rubber obtained in the same manner as in Example 1 except that n-butyllithium (n-hexane solution 9.80 mmol) was used, according to the formulation shown in Table 3, Laboplast. The mixture was kneaded in a mill to obtain a compounded rubber, which was molded into a sheet with a 6-inch roll and then vulcanized under the conditions of 160 ° C. for 15 minutes. The impact resilience of the vulcanized rubber was measured and evaluated.

Comparative Example 2 A polymer rubber obtained in the same manner as in Comparative Example 1 except that n-butyllithium (n-hexane solution 10.4 mmol) was used was kneaded in the same manner as in Example 3. Compounded rubber was obtained by molding, and this was molded into a sheet with a 6-inch roll and then vulcanized under the conditions of 160 ° C. for 15 minutes. The impact resilience of the vulcanized rubber was measured and evaluated. The results of Example 3 and Comparative Example 2 are shown in Table 4.

It was shown that each of the examples has a high impact resilience as compared with the comparative example.

[0040]

[Table 3] * 1: N-339 is used * 2: Anti-Cene 3C (Sumitomo Chemical Co., Ltd. anti-aging agent) * 3: Soxynol CZ (Sumitomo Chemical Co., Ltd. vulcanization accelerator) * 4: Sunnock N (Ouchi Shinko Chemical Co., Ltd.) Made)

[0041]

[Table 4] * 1 Modified compound A: 1- (4-N, N-dimethylaminophenyl) -1
-Phenylethylene

[0042]

As described above, according to the present invention, it is possible to provide a modified diene polymer rubber excellent in fuel economy, a method for producing the same, and a rubber composition using the polymer rubber.

Continued front page    (72) Inventor Katsunari Inagaki             Sumitomo Chemical Co., Ltd. 1-5 Anezaki Kaigan, Ichihara City, Chiba Prefecture             Business F-term (reference) 4J002 AC01W AC02W AC03W AC08W                       AC11X FD010 FD200 GC00                       GL00 GN01 GT00                 4J100 AB00Q AB02Q AB03Q AB04Q                       AB15Q AB16Q AS01P AS02P                       AS03P AS04P BA31H BC43H                       CA01 CA04 CA27 CA31 FA08                       HA35 HA61 HB14 HC48 HC83                       HE14 JA29

Claims (4)

[Claims] 1. An active conjugated diene-based polymer having an alkali metal terminal obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent using an alkali metal-based catalyst. On the other hand, a modified diene polymer rubber obtained by reacting a 1,1-diphenylethylene compound represented by the following general formula (1). (In the formula, R ₁ and R ₂ represent an alkyl group or an alkoxy group having 1 to 8 carbon atoms.) 2. The modified diene polymer rubber according to claim _1, wherein R ₁ and R ₂ are a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group or a butoxy group. 3. An active conjugated diene-based polymer having an alkali metal terminal obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent using an alkali metal-based catalyst. On the other hand, a method for producing a modified diene polymer rubber, which comprises reacting a 1,1-diphenylethylene compound represented by the general formula (1) according to claim 1. 4. A rubber composition containing the modified diene polymer rubber according to claim 1 in an amount of 10% by weight or more in a rubber component.